Vacuum pump and method of operating same



Feb. 6, 1923, LM MZL L. F. HOFFMAN. VACUUM PUMP AND METHOD OF OPERATING SAME.

FILED JAN. I9, 1921. 4 SHEETS-SHEET W 1 N VEN TOR.

A TTORNEY.

Feb. 6, 1923. 11,444,121 L. F. HOFFMAN.

VACUUM PUMP AND METHOD OF OPERATING SAME.

FILED J'AN;I9|192I- 4 SHEETS-SHEET Z.

I N VEN TOR.

Feb. 6', 1923. 1,444,121. L. F. HOFFMAN. VACUUM PUMP AND METHOD OF OPERATING SAME.

' FILED JAN. 19; 1921- 4 SHEETS-SHFET 3.

1N! EN TOR.

A TTORNEY.

Feb. 6, 1923. 1,444,121. L. F. HOFFMAN.

VACUUM PUMP ANDJIIETHOD 0F OPERATING SAME.

FILED JAN. 19. 1921. 4 SHEETSSHEET 4.

NVEN TOR.

MW Q Patented Feb. 6, i923.

rat

LEON F. HOFFMAN, OF FRANKLIN, PENN MATIC TOOL COMPANY, OF NEW YORK,

VACUUM PUMP AND METHOD OF OPERATING SAME.

Application filed January 19, 1921.

and use respectively relate, to make and use the same.

The main object of this invention is, to provide a vacuum pump which shall be considerably simplified as compared with those heretofore in use, in the respect that inlet valves are dispensed with and the inlet port is piston controlled.

Another object is, to provide a vacuum pump having a discharge valve adapted to be both automatically and manually unseated, for the respective purposes of permitting the discharge of any incompressible fluid from the cylinder, and for the easy starting, loading and unloading of the pump.

The construction whereby these objects are attained is clearly shown in the drawrings which form a part of this specification and in which:

Fig. 1 is a central, vertical, longitudinal section through the vacuum cylinder and one of its discharge valves.

Fig. 2 is a section taken centrally of a discharge valve organization, and showing the same in its normal, seated position in relation to the cylinder port with which it co-operates, also showing the valve plates closed.

Fig. 3 is a section taken centrally of said valve organization, also showing the same in its normally seated position with reference to the port with which it co-operates,

but showing the valve plates open, as when the discharge of air through the valve is normally taking place.

Fig. 4- is asection taken centrally of said discharge valve organization showing the same in the manually unseated or unloading position with reference to the cylinder port with which it co-operates, also show- Serial No. 438,367.

- ing the valve plates in the discharge position. Fig. 5 is a plan view cia'lly termed a duplex improved vacuum pump.

The main points of novelty in the construction here shown, and upon which the protection of Letters Patent is sought are:

The piston'controlled inlet port and the construction, application and operation of the discharge valve, the location of the discharge chamber in the lower portion of the pump cylinder, and the location of the outlet for said discharge chamber at the bottom of said chamber whereby the possibility of an accumulation of liquid in said chamber 1s obviated. It is, therefore, to these features and details that thespecifi'cation is mainly directed, and'the claims specifically drawn. 1 The construction here illustrated is as folows:

Through the wall of the vacuum cylinder 1 is formed an inlet port 2 which is arranged to be controlled by the piston 3, in the following manner; I

When the piston moves to one end of its stroke, as indicated by the arrow in Fig. 1, a vacuum is caused or tends to form in that end of the cylinder from which the piston is moving; this vacuum becomes more and more complete until the edge of the piston at the vacuum. face thereof, uncovers "said inlet port 2, at which juncture the air passes into the cylinder as indicated by the arrow, through said port For the purpose of discharging the air which is thus drawn into the cylinder, discharge-valve ports 4 are formed through the heads 5 and 6, in proximity to the lower portion of the bore of said cylinder. For the purpose of controlling said ports, I supply the same with a valve organization as shown in Figs. 2, 3 and 4. Said organizationcom prises the following details:

A valve-seat member 7 valve-plates 8 and 9, valve springs 10, a valve keeper 11, a valve stud 12 which passes centrally through said seat and said keeper, a castle nut 13 by means of which said seat 7 and-keeper 11 are firmly secured together upon said stud, a lifting sleeve 14, provided with a socket for the reception of the upper end of said stud 12 and in which it is secured by means of of what is commerarrangement of my Between the upper face of head 16 and the lower face of said cover 19, is inserted a compression spring 20. which exerts a sufficient pressure upon the valve organization to retain said seat member 7 thereof upon its cylinder seat 21 under all normal conditions of service. The object of said spring. however, is to give to the valve organization a yieldability whereby said seat member T with its associated organization. may be raised from said cylinder seat either manually. by operating the hand-wheel l7.-see Fig. 4. or automatically. as by the presence and force of an incompressible fluid in the cylindersee Fig. l.

My improved vacuum pump is suitable for use in any service where a vacuum pump is employed. but it has been found to be particularly adapted to the requirements of sugar refineries. In this service. at the stage, and in the receivers where vacuum is employed. syrup is present. and small quantities of it may be drawn into the cylinder of the pump: \Vhen this occurs. it is necessary that provision be made for the discharge of this syrup from the cylinder in such a way as to cause. no damage. to the cylinder. the piston or the discharge valves.

By the provision of the yieldablyseated valve organization, as above described. said necessity is fully and effectually met; in such a case the valve seat member 7 is raised from the cylinder seat 21. by the incompressible fluid and the whole valve organization. including the hand-wheel 17 is moved bodily outwardly, as shown in Fig. 1, thus permitting the discharge of the liuid and relieving the cylinder. piston and discharge valve of any injurious strain. Another object of providing said yieldablyseated valve organization is. to facilitate the easy starting and the unloading of the pump.

The pump is started in the following manner, and for the purpose of this explanation, see Fig. 5. First close the inlet throttles E and F which are in the inlet line connecting the piston-controlled inlet port with the chamber from which the air is to be pumped. Then open the discharge valves by turning the handwheels A. B, C, D. 'lhen start the pump: when the pump has attained full speed. valves A. B. C, D are closed. allowing a few seconds to elapse between the closing of each valve -where a single valve is used in each cylinder head. or each set of valves in the same end of the pump cylinder head where more than one valve is used: then open one of the throttle valves slowly. then the other in the same manner. This method of starting brings the pump gradually up to its maximum working vacuum without realizing the peak load experienced by the ordinary vacuum pumps.

It may at times be desirable to unload or arrest the normal action of the pump without stopping same: in this case, the discharge valves are manually unseated by turning the hand-wheels 1T. whereupon air may both freely enter at and be discharged from the discharge valve ports.

Attention is hereby called to my co-pending application Serial Number (305.061. filed December 9122. for valves for air pumps. and means for actuating same.

I claim the following:

I. In a vacuum pump. in combination, a pump cylinder having an air inlet port through the wall thereof arranged to be piston controlled. a discharge chamber in the lower portion of said cylinder. an outlet port leading from the bore of said cylinder into said discharge chamber and having a valve-seat formed about the discharge chamber face thereof, a discharge valve organization yieldably seated upon said seat manually unse'atable. therefrom to unload the pump, and a pump piston operable within said cylinder controlling said inlet port; said discharge chamber being provided with a discharge opening positioned below said valve organization, for the purpose set forth.

2. In a vacuum pump. in combination, a pump cylinder having features thereof, in addition to the bore. an inlet port through its wall communicating with said bore and arranged to be piston-controlled, a discharge chamber positioned in the lower portion of said cylinder. an outlet port leading through the wall of said cylinder from said bore to said chamber and having a valve seatformed about the discharge chamber face thereof. a discharge outlet for said chamber positioned below said outlet port. a valve organization yieldably seated upon said seat, a valve in said organization normally controlling said port for the discharge of air therethrough. said organization being automatically unseatable from said seat by the action and for the discharge of non-compressible fluid through said port, and a piston operative in said bore controlling the admission of air through said inlet port.

3. In a vacuum pump, in combination, a pump cylinder having as features thereof in addition to the usual bore, an inlet port through the wall of said cylinder arranged to be piston controlled, a discharge chamberin the lower portion of said cylinder, an outlet port leading through the wall of said cylinder from said bore to said chamber and having a seat for a valve organization formed about the discharge chamber side of said port, a discharge port for said dis charge chamber positioned below said out let port, a discharge valve organization seated upon said seat, a valve in said organization normally controlling the discharge of air through said organization, said organization being automatically unseatable from said seat for the discharge of non-compressible fluid through said outlet port and manually unseatable therefrom at will for the purposes set forth.

4. The method of starting a vacuum pump having a piston-controlled inlet port, which comprises the following steps: closing the throttle valve in the inlet pipe leading to said port, then unseating the dischargevalve organization, then starting the pump, then gradually seating said discharge-valve organization so as to cause the valve thereof to discharge its normal function, then opening the throttle in said inlet pipe.

5. The method of starting a vacuum pump having a piston-controlled inlet port and a plurality of manually unseatable discharge-valve organizations, which comprises Qthe following steps: unseating said dis- "charge valves'from their respective seats in the Walls of the cylinder of said pump before said pump is started, then starting the pump, then seating said discharge-valve organizations one by one so as to cause the valve in each thereof to perform its normal function thus causing the pump to assume its normal operation by steps corresponding to the number and seating of said discharge valve organizations.

(3. The method of starting a vacuum pump having a piston-controlled inlet port and a plurality of discl'iarge-valve organizations, which comprises the following steps: closing the throttle valve in the inlet pipe leading to said piston-controlled port, manually unseating said discharge-valve organizations so as to permit both the egress and ingress of air through the ports normally controlled by said organizations, then starting the pump, then seating said dischargevalve organizations one by one, so as to restore their normal functions, then opening said throttle in said inlet pipe.

7. The method of starting a pump having a piston-controlled inlet port and one or more manually unseatable discharge valves, which consists in unseating said discharge valve or valves, then starting the pump, then closing said valve or valves, whereby the pump is brought to its normal capacity in steps corresponding to the numher and closing of discharge valves employed.

8. The method of starting a vacuum pump which consists in, closing the inlet to the pump cylinder, then unseating the discharge valve, then starting the pump, then seating the discharge valve, then opening said inlet.

In testimony whereof 1 aflix my signature in presence of two witnesses.

LEON F. H01 Fh'li'iN.

vacu l1 1 n Witnesses R. P. Cownv, .D. V. Forums. 

